lobley



Aug. 25, 1931. A. G. LOBLEY 1,320,668

I ELECTRIC FURNACE Filed Aug. 7, 1929 3 Sheets-Sheet l Inga/r01: l7 6 @La 6 cy arrow/5n Aug. 25, 1931. A. G. LOBLEY ELECTRIC FURNACE sSheets-Sheet 2 Filed Aug. '7, 1929 m m V w Aug. 25, 1931. A. G. LOBLEY1,820,668

ELECTRIC FURNACE Filed Aug. 7, 1929 3 Sheets-Sheet 5 WW h w ATTORNEYPatented Aug. 25, 1931 UNITED STATES PATENT OFFICE ALFRED GLYNNE LOBLEY,F BIRMINGHAM, ENGLAND, ASSIGNOR OF ONE-HALF T0 BIRMINGHAM ELECTRICFURNACES LIMITED, OF BIRMINGHAM, ENGLAND, A COM- PANY OF GREAT BRITAINELECTRIC FURNACE Application filed August 7, 1929, Serial No. 384,065,and in Great Britain December 28, 1928.

This invention has reference to furnaces of the rotary or rotating-drumtype as used for the annealing or other heat-treatment of small metalproducts, such as cartridge cases,

, and proposes to provide an improved con struction of electric furnacewhich is adapted to operate on continuous recuperative principles byenabling an exchangeof heat between hot work which is being conveyedfrom the treatment region and the work which is being carried to thesaid region.

According to the said invention, the workconveyor is adapted to berotated within a stationary casing and relatively to a stationaryheaterstructure Whose casing is normally connected to, or forms acontinuation of, the conveyor casing but is separable or removable fromthe latter to enable access to be obtained to the interior of thefurnace-chamher wherein the resistance elements are mounted.

The conveyor is so constructed internally that when the same is rotatedrelatively to the stationary heater, the work charged thereinto will beconveyed through one compartment to the heated or treatment end andthere be transferred to another compartment wherethrough theheat-treated work is returned or conveyed, in the reverse direction,

to the delivery or discharge aperture. During this return travel throughthe rotating structure, the outgoing hot work in the one compartment isconstrained to contact with the walls (which are made of heatconduct- 85ing metal) of the chamber containing the ingoing work, and as thearrangement of the conveyor in relation to the heater provides for asubstantial travel of the incoming and outgoing work within the part ofthe conveyor that is external to the heating chamber,

it follows that effective heat-exchange is provided for and that theingoing work is materially pre-heated before arriving at the part of theconveyor where the work comes under the heater treatment and istransferred from the one compartment to the other.

A furnace or heat-treatment installation constructed in accordance withan embodiment of the present invention is shown in the 5 accompanyingdrawings in which Figure 1 is a longitudinal section showing the generalarrangement.

Figure 2 is a view showing a half longitudinal section of the furnaceand of the stationary conveyor-casing and a half plan of theconveyor-drum.

Figure 3 is a section of Figure 2 on the dotted line 33.

Figure 4 is a View showing, on the right hand side, a half elevation ofthe bearing system provided for supporting the charging-hopper end ofthe conveyor, and, on the left hand side, a half elevation of thebearings supporting the furnace end of the said conveyor.

Figure 5 shows, on the right hand side, the arrangement of the bearingsthat extend into the casing to support the conveyor intermediate thecharger and furnace ends, whilst the left hand end of the view shows ahalf elevation of the arrangements for supporting and driving the rotaryconveyor at its hopper end.

In the structure illustrated, the inner work-conveyor cylinder at andthe annular space Z) between the inner and outer cylinders a c, arerespectively furnished with systems of spiral conveyor blades a 0 ofopposite pitch so arranged that, during rotation of the said conveyorrelatively to the furnace part i of the installation, work in the onechamber or cylinder will be conveyed or carried along in the oppositedirection to the work in the other chamber, or be made to traverse,counter-flow fashion, from the feed hopper 0 along the one chamber a tothe transfer aperture f and thence in the reverse direction along theother chamber Z) to the delivery or discharge chute g.

lVhere the conveyor is driven counterclockwise and the inner cylinderreceives the work from the feed hopper, the conveyor in the said innercylinder is fitted with righthand spiral blades and carries the workforward or inwardly towards and through the resistance-heated region itto the transfer chamber, where the heated work falls by gravity into theleft-hand conveyor-spiral of the outer chamber and is returned along thelatter to the feed end whence it is finally discharged or allowed togravitate into a delivery chute. During this return flow, the heatedwork traversing the chamber b is constrained to move in contact with thewalls of the inner cylinder containing cold or relatively cold work, andas the said inner cylinder is made of heat-conducting metal, aneffective heat exchange takes place between the incoming and outgoingwork, enabling the latter recuperative'ly to heat the ingoing workduring its travel towards the resistanceheated region.

The resistance-heater elements or units 31 of the heater or actualfurnace part i' of thestationary structure are preferably arranged in aheating chamber 2'? that surrounds the transfer end of the conveyor,which latter is substantially longer than the said heating chamber toensure the incoming and outgoing work having to traverse substantialdistances through regions of the conveyor external to the actualfurnace, in order to enable useful pre heating of the incoming work.

I That part of the conveyor which is externalyto the heater is enclosedwithin a suitalblyla ged and stationary insulating casing is which issuitably carried on the frame of theinstallation and is built up oflongitudinally-divided sections or halves k 76 to enable the assembly ofthe said casing around theconveyor." The inner end of this casing isbolted or otherwise det'achably secured to the corresponding end of theheater-casing at i aand the bearings that support theheate r end of thesaid conveyor are. so constructed arranged (such as hereinafterdescribed) that, when it is desired to obtain access to the interior ofthe heatingehainber, as for inspecting or replacing resistances, theheater structure, which supported on a wheeled truck or trolley runningon rails embodied in the under-fraineof the installation, may bedisfromthe stationary casing of the conveyor and run back clear of theSL1Cl,COI1

veyor whiehremains supported by the bear i'ngs provided for carrying thesame at the hopper or charging end and ntermed ate thethopper and theheater or transfer end.

.To enable this, and also to provide for the adequate support of therotating conveyor and its load during normai working, the charging orhopper end (4 of the conveyor is supported, adjacent to the chain wheela that drives the rotary parts, by a system of bearings m whose bracketsare carried by the under-frame of the structure, whilst the other orheater end of the conveyor has a trunnion a that normally extendsthrough an aperture the end-wall of the heater-casing and is supportedby bearings m whose brackets are fixed to the said casing which arehoused in a heat-insulated chamber m attached to the outside of thestructure, so that when the heater part is disconnected and run awayfrom the casing 70, it carries the conveyor-bearings m with it.

Further intermediate bearings for the conveyor are provided by a systemof rollers 11 which are bracketed, externally to the casing 70 on theunder-frame, but parts of wliich extend through apertures 70 in the saidcasing and are engaged by a fiangea that surrounds the middle portion ofthe conveyor. These intermediate bearings n and 'the hopper-end bearingsm serve to support the conveyor when the heater-end trunnion a is leftunsupported by the running back of the furnace on its trolley,

The feed or charging hopper e ofthe conveyor is a part of the rotatingunit and is supported by'bearings'at 0 whilst the delivery aperture p ofthe said conveyor is arranged to conic into register, once during eachrotation of the conveyor, with the delivery chute g which is carried by,and extends through the wall of, the stationary casing Ii: as shown inFigure l.

Having described my invention, what I claim and desire to secure byLetters Patent is 1. A furnacecomprising a rotatable work holding drum,a frame, a' stationary casing supported by the frame and surrounding apart of the drum, a stationary furnace structure surrounding theremaining part of the drum and having heating elements therein, meansfornorinally securing the casing and furnace structure in fixedrelationship, the furnace structureliaving a bearing associated with itsouter end, a trunnion carried by the drum and rotatably engaging saidbearing, and means supporting the furnace structure to permitlongitudinal movement thereof in a direction away from thefcasing upondisconnecting the same from the'casing, as and for the purpose setforth.

2, A furnace comprising a rotatable work holding druin having" atrunnion upon its outer end, a frame, bearings carried by the frame andengaged with the drum, a stationary casing surrounding a part of thedrum, a stationary furnace structure surrounding the remaining part ofthe drui'n and having heating elements therein, the adjacent ends of thecasing and furnace structure being normally connected, the furnacestructure having a b'earing associated with its outer end adapted to,rotatably receive, said trunnion, rails, wheels carried by the furnacestructure for movement on the rails, whereby the furnace structure whendisconnected from the casing is adapted to travel on the rails, as andfor the purpose set fort h. e

In testimony whereof I hereunto afli'zt my signature.

ALFRED GLYNN'E LOBLEY.

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